Transmission of zoonotic diseases

Zoonoses Associated with Cats

This document provides information on various diseases that can be passed from cats to humans. Often these diseases do not make the animal appear sick but can cause serious illness in humans. Persons with specific medical conditions such as a chronic illness, immunodeficiency and pregnancy may be at higher risk of developing disease or complications from a zoonotic disease and should consult with their physician before working with animals.
The zoonotic diseases associated with cats include rabies, capnocytophagosis, pasteurellosis, cat scratch disease, ringworm, sporothrichosis, tularemia, plague, Q fever, and external parasites, campylobacterosis, salmonellosis, infections with pathogenic E. coli, cryptosporidiosis, giardiasis and toxoplasmosis.


Diseases associated with bites, scratches or direct contact
Diseases associated with bites, scratches or direct contact Rabies is a fatal viral infection that can be transmitted by bites, scratches and mucus membrane exposure from an infected animal. Cats are the most frequently reported domestic animal diagnosed with rabies in North America. Free roaming outdoor cats may acquire rabies from bats, raccoons, skunks and other wildlife. Infected animals often exhibit neurological symptoms and unusual behavior before death. There is an effective vaccine available for people and most domestic animals including cats. Cats that have not been vaccinated for rabies and cats with undiagnosed neurological disease should be treated with caution to avoid bites and scratches. If a person is bitten or scratched by a suspect animal, they should report the incident and seek post-exposure rabies prophylaxis from a medical professional. Persons who routinely work in high risk activities should be vaccinated against rabies. Capnocytophaga canimorsus and Pasteurella multocida are bacteria commonly found in the mouths of healthy dogs and cats and can be transmitted to people by biting. People may develop a local bacterial infection, or life-threatening sepsis. People with pre-existing disease or immunodeficiency have a higher risk of complications and should consult with their personal physician.
Cat scratch disease caused by Bartonella hensalae is a bacterial infection that is transmitted by bites, scratches and flea bites. Young cats under a year of age are more likely to carry the disease and typically exhibit no symptoms. Infection in humans often presents as a pustule at the site of infection associated with swollen lymph nodes and a fever.
Dermatophytosis is a fungal skin infection commonly known as “ringworm” and is seen in both animals and people as scaly round areas of hair loss. Transmission of ringworm is by direct skin-to-skin contact with an infected cat. Young cats and kittens are more likely to carry the disease and infect people.
Sporothrix schenckii is a yeast infection that causes skin nodules and ulcers in cats, dogs and horses. Transmission to people can occur with direct contact with lesions on infected cats. Persons should use gloves and hand-washing when handling any animal with apparent skin disease.


Diseases associated with vectors or contaminated materials
External parasites such as fleas, ticks, lice and mites are occasionally transmitted by close contact with an infested cat or handling infested bedding. Animals and animal housing areas should be routinely treated for external parasites.
Free roaming cats and cats that hunt are at risk for developing tularemia and plague. Tularemia is a bacterial infection of wild rodents and rabbits that occasionally infects cats that hunt or drink contaminated water. People can be infected by contact with infected body fluids and tissues, oral ingestion and inhalation of contaminated water or materials and tick bites. Plague caused by Yersinia pestis is endemic in wild rodents in the Southwest. Cats acquire the infection by flea bites and hunting infected rodents. Cats may develop septicemic and pneumonic plague which can be transmitted to people by inhalation, contact with the mouth, tissues and body fluids of an infected cat as well as flea bites. Disease in people can be severe and requires prompt medical diagnosis and treatment. Plague is primarily found in the Southwestern United States and is unlikely to be diagnosed in cats in the Northwest.
Q fever caused by Coxiella burnetti can cause abortion & reproductive disease in pregnant cats. There is an especially high concentration at the time that an infected cat gives birth, so particular care needs to be used in handling new born kittens, placental tissues and other products of conception. These agents can be acquired by exposure to placental membranes and fetuses from infected cats and by aerosol. Immunocompromised persons are at higher risk of developing severe disease and complications from both cat scratch disease and Q fever.
Salmonellosis, campylobacterosis, cryptosporidiosis, giardiasis and infections with pathogenic E. coli are acquired by contact and oral ingestion of fecal material from infected cats. Animals infected with these bacterial and protozoal diseases often have diarrhea but some animals may show no symptoms of disease. Toxoplasmosis is an intestinal protozoal infection in cats. Cats typically do not exhibit any disease symptoms but shed infectious oocytes in their feces. Humans are infected by accidental oral ingestion of oocytes in cat feces or ingestion of tissue cysts in undercooked meat. Toxoplasma infection during pregnancy can result in birth defects including mental retardation and blindness. Avoid direct contact with cat feces and urine and use gloves and hand-washing to avoid accidental oral ingestion of animal waste. Any animal with diarrhea should be suspect of having a zoonotic disease.


Transmission of zoonotic diseases
Transmission of zoonotic diseases from animals is primarily by direct contact, oral ingestion, indirect contact with insect vectors and contaminated inanimate objects, or inhalation of aerosolized materials. We can protect ourselves from most diseases by using the following procedures:

• Handle animals appropriately and safely to avoid bites and scratches.
• Thoroughly wash any bite or scratch wounds and report bite and scratch injuries.
• Do not eat, drink, apply makeup or use tobacco products while handling animals or in animal housing areas.
• Wear gloves when handling animals, animal tissues, body fluids and waste and wash hands after contact.
• Wear dedicated protective clothing such as a lab coat or coveralls when handling animals. Launder the soiled clothing separate from your personal clothes and preferably at the animal facility.
• Wear respiratory protection when appropriate.
• Keep animal areas clean and disinfect equipment after using it on animals or in animal areas.
• Report ill animals so that they can receive veterinary care.

Most importantly, familiarize yourself about the animals that you will be working with and the potential zoonotic diseases associated with each species. If at any time, you suspect that you have acquired a zoonotic disease, inform your supervisor and seek medical care.